The present invention relates to processes for manufacturing substrates and, more particularly, to processes suited for mass production of a highly integrated semiconductor devices.
As demand for smaller, more densely featured semiconductor devices increases, methods for improving device manufacturability and reliability are constantly evolving. Manufacturing a modern semiconductor device requires many steps or processes. These processes include a myriad of additive and subtractive processes which deposit or remove material stacks to and from a semiconductor device. In addition, one or more cleaning process may be necessary to prepare a semiconductor device for each additive or subtractive process. In some examples, manufacturing complications may arise because surfaces of a semiconductor device are typically not homogenous. That is, a semiconductor device's surface may include any number of metals or dielectric materials. Further manufacturing complications may arise because dielectric and metal lines may be extensively interleaved on a semiconductor device surface. Extensive interleaving of different materials may result in undesirable side interactions that disrupt manufacturing processes. For example, in a deposition process, it may be desirable to deposit material only on a conductive region or a dielectric region, but not both. Extensive interleaving of disparate materials may hinder selective reactivity because the physical properties of one material may adversely affect a reaction on another material. Thus, selective reactivity may be difficult or impossible to achieve.
At least some methods for achieving selective reactivity focus on selecting reactions targeted toward the more reactive surface. For example, one skilled in the art will recognize that conductive regions are typically more reactive than dielectric regions. As such, many prior art solutions have relied on utilizing reactants that interact with the more highly reactive conductive region. Unfortunately, side reactions on adjacent dielectric regions may poison a deposition layer thus rendering a semiconductor device unreliable. This phenomenon is particularly prevalent in wet process applications. In wet processes, surface molecules on a dielectric region may act as nucleation sites that result in material deposition or particle formation on the dielectric region. In addition, dielectric regions are often hydrophobic, which may decrease the wetted surface of adjacent conductive regions. As a result of these characteristics, film morphology may suffer due at least in part to undesirable particle formation on dielectric regions and incomplete reaction on conductive regions. In some instances, cleans or pre-cleans may be required to remove undesirable deposited materials, which may, in turn, add to manufacturing time and cost.
It may also be appreciated that many processes in semiconductor manufacturing require extreme operating conditions or hazardous materials to achieve desired results. For example, Physical Vapor Deposition (PVD) describes a family of thin-film coating processes which are applied under vacuum conditions of 10−2 to 10−4 Torr. Another example of a process requiring extreme operating conditions is Chemical Vapor Deposition (CVD). CVD is a thin-film coating with a diffusion type bond that results from the reaction between various gaseous phases and the heated surface of a substrate. CVD is sometimes referred to as a “hot coating” because the process approaches temperatures around 1900° F. One example of a process utilizing hazardous materials is pre-cleaning. Pre-cleaning is a type of process that typically utilizes large amounts of variant acid/base or organic solvents, which, in some examples, may be highly corrosive. Although all of these processes have found wide acceptability in the industry, their use often requires specialized tooling and handling requirements to avoid operator exposure and environmental contamination. In addition, these processes are often time-consuming, which may further add manufacturing time and costs.
Methods which improved selective reactivity of target surfaces to enhance film morphology and reduce undesirable particle formation, which do not require extreme operating conditions or hazardous materials may be desirable. As such, methods for treating substrates in preparation for subsequent processes are presented herein.